[danim]

No that's probably the original add inches method but that will normally leave you with a band loose and cups too small the best way is find your under bust measurement use that or as close as you can find to that then try on different cups there's no real accurate measurement rule for cups because there's much more to breast volume than a chest circumference it depends on so many different things so allways measure only for the band it should fit very firm and only fit 2 fingers under it don't be fooled by it being tight because your cups are too small the under wire must be close to starting at armpits(no" armpit cleavage/folds)" or breast tissue will be pushed out of your breasts and it will be more use to go braless than use something badly fitting.

Thank you BonitaDDs for your anwers. I could go braless since I´m flat.